Manufacture of nuts for screw bolts, etc.



Nov. 13 1923.

F. D. ARCHIBALD MANUFACTURE OF NUTS FOR :SCREW BOLTS,

ETC

Filed May 9, 1921 Fatented Nov. 13, 1923.

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FRANCIS D. ARCHIBALD, MAMABONECK, NEW YORK.

MANUFACTURE OF NUTS FOR SCREW BOLTS, ETC.

Application filed May 9, 1921.

To all whom it may concern:

Be it known that 1, Farmers D. ARCHI- BALD, a citizen of the United States, residing in Mamaroneck, county of Westchester, and 1 State of New York, have invented certain new and useful Improvements in the Manufacture of Nuts for Screw Bolts, Etc, of which the following is a specification.

The main object of my invention is to simplify and cheapen the manufacture of screw nuts generally, and at the same time to attain a perfectly accurate product of exceptional strength and tenacity having a uniformly homogeneous molecular structure throughout, my method also practically eliminating waste of material, and reducing labor and cost of production to a minimum degree.

To this end my invention consists essentially in the mechanical process herein described and claimed specifically of forming a tubular nut blank by reducing externally a metallic tube of prescribed and maintained internal diameter in such manner that its configuration is changed from cylindrical to angular form, the tubular nut blank thus created being then cut into suitable nut lengths, and the individual nut blanks thus evolved being then internally screw threaded, all as hereinafter fully set forth.

In the accompanying drawings, Fig. 1, is a sectional elevation, illustrating diagrammatically my method of making tubular nut blanks;

Fig. 2, is an elevation, taken at right angles to Fig. 1, showing the compressionrolls, with the tubular nut blank therebetween;

Fig. 3, is an elevation of the tubular blank as prepared for initiative introduction between the rolls;

Fig. 4, is an end view thereof, looking in the direction of the arrow a and on plane of line 4-4;, Fig. 3;

Fig. 5, is an end view thereof looking in, the direction of the arrow a, and on plane of line 55, Fig. 3;

Fig. 6, is an end view of a nut blank as severed from the finished tabular blank;

Fig. 7, is a view illustrating the separation of the finished tubular blank into separate nut blanks;

Fig. 8, is a section of a finished nut.

In carrying out my process of manu- Serial No. 467,790.

facture I take a tube B, of prescribed internal diameter and pass it over a suitably supported mandrel m, first however shaping the forward extremity Z), of the tube, as

lndicated for instance in Flg. 3, by swaging or otherwise, for a distance sufficient to facilitate its preliminary introduction between the reducing rolls, R, R, which latter are mounted in any well known or suitable manner with their axes r, 7', at right angles to but in vertical alignment with the mandrel m, as indicated by the axial plane 29, 39, Fig. 1.

The forceful rotation of the rolls R, R, in the direction of the arrows, Fig. 1, will of course change the external configuration of the tube B, in accordance with the peripheral shape of the rolls R, R, provided that the external diameter of the tube B, is sutlicient for the purpose. Preferably the cylindrical tube B, is of a diameter, as in Figs. '1 and 2, equal to the maximum diameter of the nut blank tube formed by the rolls R, R, the displacement and flow of metal caused by the latter tending to lengthen the blank while reducing the sides thereof to the requisite shape. Thus the greater diameters of the end of the blank shown in Fig. 2, equal the primary maximum diameter of the cylindrical portion of the tube B. It is obvious however that a tube of smaller external diameter might be used if it afforded sufficient margin of lateral displacement of metal from cylindrical form to admit of the angulation externally of the resultant blank, so that I do not limit myself in this respect, the essential feature being the use of a tube of prescribed internal diameter and of sufficient external diameter to afford, by roll compression, the required displacement, peripherally, of metal to create the flat, angular sides of the desired configuration of nut.

The nut blank as delivered by the compression rolls R, R, is sub-divided into suitable lengths to form individual nut blanks, Z), 7). This sub-division is effected by means of cutting tools, in a manner well known. in the art, the individual blanks I), being then internally screw threaded, also in a manner and by means well known in the'art.

The advantages attained by my process of manufacture of nut blanks as compared with the old method of either hot or cold punching nut blanks are numerous, and of practical importance. Thus in either hot or cold punched nut blanks the hole varies in diameter, due to the tearing and irregular displacement of metal during such punching operation, the greater diameter of hole usually occurring at the center of the nut, the ends of the hole (which is theoretically supposed to be of correct uni form diameter throughout) being less in diameter than the diameter of the central portion, and this defect being greater in proportion in the larger sizes of nut. Hence it is obvious that the screw pitch diameter of such a nut will be less than the pitch diameter of the thread on the bolt or stud on which the nut is to be used, so that the fit will be loose, and the connection between male and female threads will not be as strong and effective "as where both screw pitch diameters are correct and identical.

I obviate this difficulty by maintaining a perfectly cylindrical and prescribed internal diameter of nut blank, and at the same time effect economy in the screw tapping of the individual nuts because of the even resistance afforded the cutting tools, and the uniform amount of material removed thereby from a true hole such as attained by my method. 7

Furthermore in cutting individual nut blanks from my tubular nut blank the only material lost is that necessarily removed in the actual severance, which is small in comparison to the amount of material lost in the-formation of a hot or cold punched nut, and the subsequent trimming operation rendered necessary thereby to finish the nut,

involving the treatment separately of both top, bottom and sides of such a nut blan whereas'by my process the sides of the tubular blank bar are finished in the rolls before the individual nut blanks are severed from said tubular blank bar.

Again, in the old method of punohingout the nut blank considerable crystalization or even fracture of material is apt to occur due to the distortion of the metal thus treated, thereby weakening the structure of the prodnot. By my method crystalization or fracture of the metallic fibre is impossible, and a contrary effect is attained in that the metal involved is compressed evenly between the rolls and the mandrel, and the flow of metal thus induced tends to align the metallic fibre and render the same more homogenous and tenacious. Furthermore by my method of formation, the sides of the nut and the hole therein are always absolutely parallel and properly centralized, a result seldom attained 1 in punched nuts in which the sides of the finished nut are not always at right angles to the top and botom, nor equi-distant from the axes of the hole, the latter being eccentric instead of concentric as related to the mean axis of the bolt, a result rendered impossible in my case by the presence of the mandrel in the tube during the formation of the angular sides.

In the drawings I show my method as adapted to the production of a hexagonal nut by way of exemplification, it being understood that square, or any other externally fiat angular form of nut, may thus be pro- 1. The method herein set forth of manufacturing nut blanks of the character designated in one continuous operation from me talic tubes of prescribed internal diameter, consisting in preliminarily swaging the tube to the size and shape of the matrix between reducing rolls maintainng such internal diameter by mandrel-support while changing the tube externally to suitable flat sided configuration in cross section by passing it be tween. compression rolls at right angles to the mandrel, and maintaining a prescribed internal diameter and an external diameter to afford, by roll expression, the requisite peripheral displacement of the metal to create the desired angular configuration of the nut blank, substantially as and for the purpose set forth.

2. The method herein set forth of manufacturing nuts of the character designated from metallic tubes of prescribed internal diameter, consisting in preliminarily swaging the tube to the size and shape of the matrix between reducing rolls maintaining such internal diamter by mandrel support while changing the exterior of the tube to suitable flat sided configuration in cross sec tion by passing it between compression rolls at right angles to such mandrel support and maintaining a prescribed internal diameter and an external diameter to afford, by roll expression, the requisite peripheral displacement of the metal to create the desired angular configuration of the nut blank cutting the nut bar thus formed into nut lengths, an internally screw threading the latter individually, substantially as and for the purpose described.

3. The method herein set forth of manufacturing nuts of the character designated from cylindrical metallic tubes of maximum external diameter and of prescribed internal diameter, consisting in swaging the end of the tube to the size andshape of the. matrix between reducing rolls, maintaining the prescribed internal diameter'of the tube. by manlit) drel support While changing the exterior of finally screw-threading the latter individuthe tube to suitable flat sided configuration ally, substantially in the manner and for the in cross section by passing it between said purpose described.

reducing compression rolls, the plane of the FRANCIS D. ABCHIBALD. 5 axes of said reducing rolls being at right an- Witnesses:

gles, to the said mandrel support, cutting the DOROTHY MIATT,

nut bar thus formed into nut lengths, and GEO. WM. MIATT. 

